CodeVerify.h revision 3f64a024dec2c080b9abde74502826b29263152a
1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* 18 * Dalvik bytecode verifier. 19 */ 20#ifndef _DALVIK_CODEVERIFY 21#define _DALVIK_CODEVERIFY 22 23#include "analysis/VerifySubs.h" 24 25 26/* 27 * Enumeration for register type values. The "hi" piece of a 64-bit value 28 * MUST immediately follow the "lo" piece in the enumeration, so we can check 29 * that hi==lo+1. 30 * 31 * Assignment of constants: 32 * [-MAXINT,-32768) : integer 33 * [-32768,-128) : short 34 * [-128,0) : byte 35 * 0 : zero 36 * 1 : one 37 * [2,128) : posbyte 38 * [128,32768) : posshort 39 * [32768,65536) : char 40 * [65536,MAXINT] : integer 41 * 42 * Allowed "implicit" widening conversions: 43 * zero -> boolean, posbyte, byte, posshort, short, char, integer, ref (null) 44 * one -> boolean, posbyte, byte, posshort, short, char, integer 45 * boolean -> posbyte, byte, posshort, short, char, integer 46 * posbyte -> posshort, short, integer, char 47 * byte -> short, integer 48 * posshort -> integer, char 49 * short -> integer 50 * char -> integer 51 * 52 * In addition, all of the above can convert to "float". 53 * 54 * We're more careful with integer values than the spec requires. The 55 * motivation is to restrict byte/char/short to the correct range of values. 56 * For example, if a method takes a byte argument, we don't want to allow 57 * the code to load the constant "1024" and pass it in. 58 */ 59enum { 60 kRegTypeUnknown = 0, /* initial state; use value=0 so calloc works */ 61 kRegTypeUninit = 1, /* MUST be odd to distinguish from pointer */ 62 kRegTypeConflict, /* merge clash makes this reg's type unknowable */ 63 64 /* 65 * Category-1nr types. The order of these is chiseled into a couple 66 * of tables, so don't add, remove, or reorder if you can avoid it. 67 */ 68#define kRegType1nrSTART kRegTypeFloat 69 kRegTypeFloat, 70 kRegTypeZero, /* 32-bit 0, could be Boolean, Int, Float, or Ref */ 71 kRegTypeOne, /* 32-bit 1, could be Boolean, Int, Float */ 72 kRegTypeBoolean, /* must be 0 or 1 */ 73 kRegTypePosByte, /* byte, known positive (can become char) */ 74 kRegTypeByte, 75 kRegTypePosShort, /* short, known positive (can become char) */ 76 kRegTypeShort, 77 kRegTypeChar, 78 kRegTypeInteger, 79#define kRegType1nrEND kRegTypeInteger 80 81 kRegTypeLongLo, /* lower-numbered register; endian-independent */ 82 kRegTypeLongHi, 83 kRegTypeDoubleLo, 84 kRegTypeDoubleHi, 85 86 /* 87 * Enumeration max; this is used with "full" (32-bit) RegType values. 88 * 89 * Anything larger than this is a ClassObject or uninit ref. Mask off 90 * all but the low 8 bits; if you're left with kRegTypeUninit, pull 91 * the uninit index out of the high 24. Because kRegTypeUninit has an 92 * odd value, there is no risk of a particular ClassObject pointer bit 93 * pattern being confused for it (assuming our class object allocator 94 * uses word alignment). 95 */ 96 kRegTypeMAX 97}; 98#define kRegTypeUninitMask 0xff 99#define kRegTypeUninitShift 8 100 101/* 102 * RegType holds information about the type of data held in a register. 103 * For most types it's a simple enum. For reference types it holds a 104 * pointer to the ClassObject, and for uninitialized references it holds 105 * an index into the UninitInstanceMap. 106 */ 107typedef u4 RegType; 108 109/* 110 * A bit vector indicating which entries in the monitor stack are 111 * associated with this register. The low bit corresponds to the stack's 112 * bottom-most entry. 113 */ 114typedef u4 MonitorEntries; 115#define kMaxMonitorStackDepth (sizeof(MonitorEntries) * 8) 116 117/* 118 * During verification, we associate one of these with every "interesting" 119 * instruction. We track the status of all registers, and (if the method 120 * has any monitor-enter instructions) maintain a stack of entered monitors 121 * (identified by code unit offset). 122 */ 123typedef struct { 124 RegType* regTypes; 125 MonitorEntries* monitorEntries; 126 u4* monitorStack; 127 unsigned int monitorStackTop; 128} RegisterLine; 129 130/* 131 * Table that maps uninitialized instances to classes, based on the 132 * address of the new-instance instruction. One per method. 133 */ 134typedef struct UninitInstanceMap { 135 int numEntries; 136 struct { 137 int addr; /* code offset, or -1 for method arg ("this") */ 138 ClassObject* clazz; /* class created at this address */ 139 } map[1]; 140} UninitInstanceMap; 141#define kUninitThisArgAddr (-1) 142#define kUninitThisArgSlot 0 143 144/* 145 * Various bits of data used by the verifier and register map generator. 146 */ 147typedef struct VerifierData { 148 /* 149 * The method we're working on. 150 */ 151 const Method* method; 152 153 /* 154 * Number of code units of instructions in the method. A cache of the 155 * value calculated by dvmGetMethodInsnsSize(). 156 */ 157 u4 insnsSize; 158 159 /* 160 * Number of registers we track for each instruction. This is equal 161 * to the method's declared "registersSize". (Does not include the 162 * pending return value.) 163 */ 164 u4 insnRegCount; 165 166 /* 167 * Instruction widths and flags, one entry per code unit. 168 */ 169 InsnFlags* insnFlags; 170 171 /* 172 * Uninitialized instance map, used for tracking the movement of 173 * objects that have been allocated but not initialized. 174 */ 175 UninitInstanceMap* uninitMap; 176 177 /* 178 * Array of RegisterLine structs, one entry per code unit. We only need 179 * entries for code units that hold the start of an "interesting" 180 * instruction. For register map generation, we're only interested 181 * in GC points. 182 */ 183 RegisterLine* registerLines; 184 185 /* 186 * The number of occurrences of specific opcodes. 187 */ 188 size_t newInstanceCount; 189 size_t monitorEnterCount; 190} VerifierData; 191 192 193/* table with static merge logic for primitive types */ 194extern const char gDvmMergeTab[kRegTypeMAX][kRegTypeMAX]; 195 196 197/* 198 * Returns "true" if the flags indicate that this address holds the start 199 * of an instruction. 200 */ 201INLINE bool dvmInsnIsOpcode(const InsnFlags* insnFlags, int addr) { 202 return (insnFlags[addr] & kInsnFlagWidthMask) != 0; 203} 204 205/* 206 * Extract the unsigned 16-bit instruction width from "flags". 207 */ 208INLINE int dvmInsnGetWidth(const InsnFlags* insnFlags, int addr) { 209 return insnFlags[addr] & kInsnFlagWidthMask; 210} 211 212/* 213 * Changed? 214 */ 215INLINE bool dvmInsnIsChanged(const InsnFlags* insnFlags, int addr) { 216 return (insnFlags[addr] & kInsnFlagChanged) != 0; 217} 218INLINE void dvmInsnSetChanged(InsnFlags* insnFlags, int addr, bool changed) 219{ 220 if (changed) 221 insnFlags[addr] |= kInsnFlagChanged; 222 else 223 insnFlags[addr] &= ~kInsnFlagChanged; 224} 225 226/* 227 * Visited? 228 */ 229INLINE bool dvmInsnIsVisited(const InsnFlags* insnFlags, int addr) { 230 return (insnFlags[addr] & kInsnFlagVisited) != 0; 231} 232INLINE void dvmInsnSetVisited(InsnFlags* insnFlags, int addr, bool changed) 233{ 234 if (changed) 235 insnFlags[addr] |= kInsnFlagVisited; 236 else 237 insnFlags[addr] &= ~kInsnFlagVisited; 238} 239 240/* 241 * Visited or changed? 242 */ 243INLINE bool dvmInsnIsVisitedOrChanged(const InsnFlags* insnFlags, int addr) { 244 return (insnFlags[addr] & (kInsnFlagVisited|kInsnFlagChanged)) != 0; 245} 246 247/* 248 * In a "try" block? 249 */ 250INLINE bool dvmInsnIsInTry(const InsnFlags* insnFlags, int addr) { 251 return (insnFlags[addr] & kInsnFlagInTry) != 0; 252} 253INLINE void dvmInsnSetInTry(InsnFlags* insnFlags, int addr, bool inTry) 254{ 255 assert(inTry); 256 //if (inTry) 257 insnFlags[addr] |= kInsnFlagInTry; 258 //else 259 // insnFlags[addr] &= ~kInsnFlagInTry; 260} 261 262/* 263 * Instruction is a branch target or exception handler? 264 */ 265INLINE bool dvmInsnIsBranchTarget(const InsnFlags* insnFlags, int addr) { 266 return (insnFlags[addr] & kInsnFlagBranchTarget) != 0; 267} 268INLINE void dvmInsnSetBranchTarget(InsnFlags* insnFlags, int addr, 269 bool isBranch) 270{ 271 assert(isBranch); 272 //if (isBranch) 273 insnFlags[addr] |= kInsnFlagBranchTarget; 274 //else 275 // insnFlags[addr] &= ~kInsnFlagBranchTarget; 276} 277 278/* 279 * Instruction is a GC point? 280 */ 281INLINE bool dvmInsnIsGcPoint(const InsnFlags* insnFlags, int addr) { 282 return (insnFlags[addr] & kInsnFlagGcPoint) != 0; 283} 284INLINE void dvmInsnSetGcPoint(InsnFlags* insnFlags, int addr, 285 bool isGcPoint) 286{ 287 assert(isGcPoint); 288 //if (isGcPoint) 289 insnFlags[addr] |= kInsnFlagGcPoint; 290 //else 291 // insnFlags[addr] &= ~kInsnFlagGcPoint; 292} 293 294 295/* 296 * Create a new UninitInstanceMap. 297 */ 298UninitInstanceMap* dvmCreateUninitInstanceMap(const Method* meth, 299 const InsnFlags* insnFlags, int newInstanceCount); 300 301/* 302 * Release the storage associated with an UninitInstanceMap. 303 */ 304void dvmFreeUninitInstanceMap(UninitInstanceMap* uninitMap); 305 306/* 307 * Associate a class with an address. Returns the map slot index, or -1 308 * if the address isn't listed in the map (shouldn't happen) or if a 309 * different class is already associated with the address (shouldn't 310 * happen either). 311 */ 312//int dvmSetUninitInstance(UninitInstanceMap* uninitMap, int addr, 313// ClassObject* clazz); 314 315/* 316 * Return the class associated with an uninitialized reference. Pass in 317 * the map index. 318 */ 319//ClassObject* dvmGetUninitInstance(const UninitInstanceMap* uninitMap, int idx); 320 321/* 322 * Clear the class associated with an uninitialized reference. Pass in 323 * the map index. 324 */ 325//void dvmClearUninitInstance(UninitInstanceMap* uninitMap, int idx); 326 327 328/* 329 * Verify bytecode in "meth". "insnFlags" should be populated with 330 * instruction widths and "in try" flags. 331 */ 332bool dvmVerifyCodeFlow(VerifierData* vdata); 333 334#endif /*_DALVIK_CODEVERIFY*/ 335